Structural preservative.



UNITED sagas ran siren.

GEORGE D. COLEMAN, QF-BROOKLINE, MASSACHUSETTS.

STRUCTURAL PRESERVATIVE.

No Drawing.

specification of Iietters Patent.

To all who mutt may concern:

Be it known that I, GEORGE D. Connamx,

.a citizen of the United States, residing at Brookline, in the county of Norfolk and Stateof Massachusetts, have invented oer-- tain new and useful Improvements in Structural Preservatives; and I do hereby declare the following to'be a full, clear, and

exact description of the invention, such as will enable others skilled inthe art to which it appertains to'make and use the same.

Thepresent invention relates toan improvement in structural preservatives.

- Experience with the structural preservative described and claimed in my co-pending application filed March 20th, 1905, Serial No. 251,172 has demonstrated its capacity to form a protective coating for steel structural work. The coating of that application consisted of a layer of slow drying \pa-int applied to the surface of the structure, anf

anchoring layer of granulated material embodied in thesurface of the pa1nt, and a layer of hydraulic cement. The specific material which formed the anchoring layer in the embodiment of that application consisted of connninuted lead which gave the coating a co-eflicient of expansion substantially identical with that of steel.

The present invention relates to anim- 'provement upon the preservative of the said application, which materially diminishes the cost of thecoating without impairing its quality.

drying paint.

According to .the present invention-the surface of the structure to be coated will.

first be cleaned, preferably by the use of a sand blast, to expose the clean metal, if the structure be of metal, andthen to'the surface thus cleaned is applied a layer of slow An excellent paint for this purpose is made of litharge and hydrated xid of lead worked up with raw linseed oil in which no drier is used.- The hydrated oxid of lead forms with the 011 a very tough adhesive material which is resilient and elastic but dense, and which will securelyattach itself to the surface of the structure irrespective of its irregularities, and which will not break or crack with the come and go of the parts thereof. While this layer of paint is still moist and tacky the surface I prefer to grind the brick 'of from 20 to 80 mesh and mix it with comminuted lead, say from to mesh in size. This mixing is preferably done with Portland cement. gether in a receptacle and. tumbled with The brick meal consists of angular particles Patented Oct. 19, 1909. Application filed November 6, 1905. Serial 1%. 286,148.

of baked earthy or clayey material, and is conveniently obtained by crushing fragments of overburntbri'ck. 'The character-' istic quality of the material is its porosity and its sharp angular nature which enables it to form a very strong bond with the by draulic cemnt applied thereto. Thenature of the bond between the brick meal and the thereby form a chemical as well as a mechanical bond between the anchoring layer and the cement. I

to a fineness the addition of a small quantity of hydraulic cement in the presence of a sufficient quantity of waterlio dampenthe materials. The best proportions for the mixture will be 850 pounds of brick meal, pounds of lead and 50 pounds of hydraulic, preferably These are placed toenough water added to dampen the contents until the particles of brick and lead and flceinent are intimately mixed. This preliminary mixing and tumbling process seems to coat the particles of brick with-metallic lead and Portland cement with the-result that the particles after having been applied to the paintcwill securely hold the layer of cement. It is to be understood, of course,

i that I do not limit myself to these proportions or to' these ingredients, but it is intended that the invention should comprehend'the employment of a slow drying paint and layer of anchoring material consisting of pulverulent baked earthymaterial and a layer of hydraulic cement. The excellent quality of a coating made of these materials recommend it to users. The surface being of hydraulic cement is insensibleto deterio- I ration by moisture or carbonicacid', or even the sulfurous acid exhaled by locqmotives standing in train sheds or passing under bridges or through tunnels, whereby the structure is preserved for a length of time.

which-cannot yet be predicted. Structures covered with'this coating do not show any alligator skin cracking appearance but are persistent in adhesion continuous in surface.

and hard and dense.

Having thus described the invention, what laid upon and united to the surface of the is claimed is: anchoring layer, forming a continuous pro- A structural preservative for iron and tecting surface insensible to deterioration by steel structures, such as tram sheds, conslstmoisture or carbonic acid or sulfurous acld, 111g of a layer of strongly adheslve slow drysubstantially as described.

ing paint applied to the surface of the struc- In testimony whereof I affix my signature, ture, and forming after hardening a hard in presence of two witnesses. and dense coating, .an anchoring layer of GEORGE D. COLEMAN.

pulverulent baked earthy material embedded \Vitnesses:

in the surface of the paint and projecting HORACE VAN E vnnim, therefrom, and a layer of hydraulic cement- E ALFRED H. HILDRE'IH. 

